1. Field of the Invention
The present invention relates to flip-up electronic product technology and more particularly, to a dual-shaft hinge for connection between a base member and a cover member of a flip-up electronic product, which enables the base member and the cover member to be biased relative to each other smoothly and accurately, preventing errors in angular difference between the two opposite lateral sides of the cover member and the two opposite lateral sides of the base member.
2. Description of the Related Art
Hinges are intensively used in flip-up mobile electronic devices, such as notebook, electronic dictionary, PDA and etc. to pivotally connect a base member and a cover member together, allowing only a limited angle of rotation between them. These hinges are commonly of a dual-shaft design. A conventional dual-shaft hinge for flip-up electronic product generally comprises a female hinge member, and two hinge shafts pivotally coupled to the female hinge member and respectively affixed to a base member and a cover member of a flip-up electronic product, and thus, the cover member of the flip-up electronic product can be opened and attached to the bottom side of the base member between, or closed and attached to the top side of the base member.
In commercial dual-shaft hinges, biasing between the first hinge shaft and the female hinge member can be achieved through screw transmission or linkage transmission. In a screw transmission type dual-shaft hinge, the first hinge shaft and the second hinge shaft are respectively configured to provide a spirally extended guide groove, and a sliding block is coupled between the spirally extended guide groove of the first hinge shaft and the spirally extended guide groove of the second hinge shaft. In a linkage transmsission type dual-shaft hinge, a linkage is coupled between one side of the first hinge shaft and one side of the second hinge shaft. However, either screw transmission type or linkage transmission type, conventional dual-shaft hinges commonly ignore an important issue, that is, two dual-shaft hinges are normally used and bilaterally connected between the cover member and base member of the flip-up electronic product, and no linking means is provided to link the two dual-shaft hinges; when the user biases the cover member relative to the base member, the two dual-shaft hinges can receive different pressures due to insufficient rigidity of the cover member. During the application of a screw transmission type dual-shaft hinge, if the applied force is not evernly distributed through the two dual-shaft hinges, errors in angular difference between the two opposite lateral sides of the cover member and the two opposite lateral sides of the base member can occur, and the user can see the occurrence of this problem. Further, because the first hinge shaft, the second hinge shaft and the sliding block are moved at the same time, the user will be unable to bias the cover member smoothly when the aforesaid errors occurred. If the user keeps biasing the cover member with more effort, a high friction between component parts will occur, shortening the lifespan of the product.